Extension for ASP.NET SignalR Backplane

NCache extends the IDependencyResolver interface with its UseNCache method which requires just the cache name and event key for the item added. This acts as the registration point for the clients against the SignalR implementation.

Note

This feature is also available in NCache Professional.

The UseNCache method takes in the following parameters:

Parameters	Type	Description
`cacheName`	`String`	Name of the cache in NCache that will store the respective item for the client to trace updates via `itemVersion`.
`eventKey`	`String`	Unique user-specified key attribute for the item added to NCache on client registration. The event key is specific to the application. Each client of the application will use the same event key while calling NCache's extension method.
`configuration`	`NCacheScaleoutConfiguration`	An object of `NCacheScaleoutConfiguration` which extends the `ScaleoutConfiguration` class and takes in `cacheName`, `eventKey`, `userid`, and `password` as members.

Prerequisites for NCache Extension for ASP.NET SignalR Backplane

.NET

Install the following NuGet packages in your application based on your NCache edition:
- Enterprise: AspNet.SignalR.NCache
- Professional: AspNet.SignalR.NCache.Professional
- OpenSource: AspNet.SignalR.NCache.OpenSource
To utilize the extension, include the following namespaces in your application in Startup.cs:
- Alachisoft.NCache.AspNet.SignalR
- Microsoft.AspNet.SignalR
The cache must be running.
Make sure to use the version 2.4.0 and onwards of ASP.NET SignalR.
For API details, refer to: UseNCache.
Make sure that the data added is serializable.
To ensure the operation is fail safe, it is recommended to handle any potential exceptions within your application, as explained in Handling Failures.
To handle any unseen exceptions, refer to the Troubleshooting section.

Modify Web.config

Add the configSections tag in <configuration> as follows:

<configuration>
  <configSections>
    <section name="ConnectionOptions"
    type="Alachisoft.NCache.AspNet.SignalR.SignalRConnectionOptions"/>
 </configSections>
</configuration>

Add the ConnectionOptions section in <configuration> to set different properties to be used at the time of client connection with the cache. For a detailed description of parameters provided in the ConnectionOptions object, refer to CacheConnectionOptions Properties.

<configuration>
  <ConnectionOptions ClientBindIp="" AppName="DemoAppName" EnableClientLogs="false" LogLevel="info">
    <Server name="20.200.21.39" port="9800"/>
    <UserCredentials userID="john doe" password="1234" />
 </ConnectionOptions>
</configuration>

Add appSettings section specifying cacheName and eventKey in <configuration> as follows:

<appSettings>
  <add key="cache" value="demoCache" />
  <add key="eventKey" value="chatApplication" />
</appSettings>

Register Clients to use NCache

Overload 1:

public static IDependencyResolver UseNCache(this IDependencyResolver resolver, string cacheName, string eventKey, string userID = null, string password = null)

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        string cache, eventKey;
        cache = ConfigurationManager.AppSettings["cache"];
        eventKey = ConfigurationManager.AppSettings["eventKey"];
        GlobalHost.DependencyResolver.UseNCache(cache, eventKey);

        //using NCache SignalR
        app.MapSignalR();
    }
}

Overload 2:

public static IDependencyResolver UseNCache(this IDependencyResolver resolver, NCacheScaleoutConfiguration configuration)

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        string cache, eventKey, userId ="", password="";
        cache = ConfigurationManager.AppSettings["cache"];
        eventKey = ConfigurationManager.AppSettings["eventKey"];
        var options = (CacheConnectionOptions)ConfigurationManager.GetSection("ConnectionOptions");
        if (options!= null && options.UserCredentials != null)
        {
            userId = options.UserCredentials.UserID;
            password = options.UserCredentials.Password;
        }

        var configuration = new NCacheScaleoutConfiguration(cache, eventKey, userId, password);
        GlobalHost.DependencyResolver.UseNCache(configuration); //using NCache SignalR
        app.MapSignalR();
    }
}

Additional Resources

NCache provides sample application for SignalR on GitHub.